1. Technical Field
The present invention relates to a method for producing an organic electroluminescence element, an organic electroluminescence element, an organic EL display device, an organic EL lighting, and an apparatus for producing an organic electroluminescence element.
2. Background Art
Since the announcement by Kodak Corp. of a layer-stacked organic electroluminescence (hereinafter, sometimes simply referred to as “EL”) element using a vapor deposition process, aggressive development of an organic EL display or an organic EL lighting is ongoing. An organic EL display or an organic EL lighting is currently being put into practical use.
In such a layer-stacked organic electroluminescence element, plural organic layers (for example, an emitting layer, a hole injection layer, a hole transport layer and an electron transport layer) are provided by stacking the layers between an anode and a cathode. As the method for forming these organic layers, a vacuum vapor deposition process is known. However, in the vacuum vapor deposition process, it is sometimes difficult to obtain a homogeneous defectless thin film, and at the same time, since a long time is required to form plural organic layers, there is a problem to be solved also in view of production efficiency of the element.
In this connection, a technique where plural organic layers of a layer-stacked organic electroluminescence element are formed by a wet film-forming method has been reported. For example, Patent Document 1 describes an organic electroluminescence element having an organic thin film formed using an organic thin film-forming solution obtained by dissolving a low molecular organic material in a solvent.
On the other hand, in the case of forming an organic layer in an organic electroluminescence element by the above-described wet film-forming method, it is generally known that when the film formation is performed in air, characteristics of the obtained organic electroluminescence element are deteriorated.
In this connection, there is disclosed a technique related to production of an organic electroluminescence element for avoiding the deterioration due to air. For example, Patent Documents 2 and 3 describe a method for producing an organic EL element in an inert gas containing moisture or oxygen in not more than a predetermined concentration.